Self-Aligned Electrode Phase Change Memory

Abstract

A phase change memory may be formed with an upper electrode self-aligned to a phase change memory element. In some embodiments, patterning techniques may be used to form the elements of the memory. The memory element may be formed as a sidewall spacer formed on both opposed sides of an elongate strip of material. The resulting elongate strip of phase change memory element material may then be singulated in the same etching step that forms the upper electrodes extending in the column direction. Thus, the memory elements may be singulated in the row direction, while, at the same time, the top electrodes are defined to extend continuously in the column direction.

1 . A method comprising:
 blanket depositing electrode material over spaced, parallel, first strips of phase change material extending in a first direction; and   patterning the electrode material in a direction perpendicular to said first direction so as to segment the first strips of phase change material into individual portions, self-aligned to each top electrode.   
     
     
         2 . The method of  claim 1  wherein said strips of phase change material include an elongate structure having at least one sidewall spacer formed of phase change material. 
     
     
         3 . The method of  claim 1  wherein blanket depositing electrode material includes forming a plurality of spaced, parallel, elongate masks, and forming sidewall spacers on the sides of said mask. 
     
     
         4 . The method of  claim 3  including forming a phase change material sidewall spacer on both sides of a parallel, elongate mask. 
     
     
         5 . The method of  claim 4  including forming a sidewall spacer between an elongate mask. and said phase change material sidewall spacer, 
     
     
         6 . The method of  claim 5  including forming a sidewall spacer on the outside of each of said phase change material sidewall spacers. 
     
     
         7 . The method of  claim 1  wherein patterning said electrode material includes forming a series of spaced, parallel, elongate second strips extending generally perpendicular to said first strips. 
     
     
         8 . The method of  claim 7  including forming a heater under said first strips of phase change material. 
     
     
         9 . The method of  claim 8  including patterning down to, but not through, said heater. 
     
     
         10 . The method of  claim 9  including filling trenches, formed by patterning, with a filler material. 
     
     
         11 . The method of  claim 10  including removing said filler material and forming a metal in place of said filler material.